Element Substrate, Inspecting Method, and Manufacturing Method of Semiconductor Device

ABSTRACT

A substrate including a semiconductor layer, where characteristics of an element can be evaluated with high reliability, and an evaluating method thereof are provided. A substrate including a semiconductor layer of the invention has a closed-loop circuit in which an antenna coil and a semiconductor element are connected in series, and a surface of an area over which the circuit is formed is covered with an insulating film. By using such a circuit, a contactless inspection can be carried out. Further, a ring oscillator can be substituted for the closed-loop circuit.

TECHNICAL FIELD

The present invention relates to an element substrate, an inspectingmethod, and a manufacturing method of a semiconductor device using theinspecting method.

BACKGROUND ART

In recent years, development of a semiconductor device fortransmitting/receiving data wirelessly (referred to as a wireless chip,an RFID tag, and the like) has been advanced.

In general, in the case of manufacturing an LSI chip, an element or acircuit for evaluating characteristics, which is referred to as a TEG(test elementary group) is formed over a substrate for forming the LSIchip. A manufacturing process of the LSI chip or a parameter used fordesigning an LSI can be tested by evaluating the TEG A wireless chip isalso formed of an LSI chip, and a TEG is provided over a substrate forforming the LSI chip in order to test a manufacturing process, and thelike.

Further, in an inspecting process of a semiconductor device, anon-contact inspecting process is suggested (see Patent Document 1).

[Patent Document 1] Japanese Patent Laid-Open No. 2003-31814 DISCLOSUREOF INVENTION

Although an LSI chip formed over a silicon wafer is known as an LSI chipfor forming a wireless chip at present, development of a chip providedover a flexible substrate (hereinafter referred to as a flexible chip)has been advanced. The flexible chip can be used for variousapplications since it is very thin and flexible.

The chip is usually evaluated by bringing a pin referred to as a proberinto contact with a substrate over which a TEG is formed so as tomeasure electrical characteristics. That is, the electricalcharacteristics are measured by contact. However, it is difficult tomeasure the flexible chip automatically by contact with a pin since itis at high risk for damaging a thin semiconductor layer. Therefore, inorder to measure by contact, it is required that a pin is accuratelybrought into contact with the chip by hand or a predeterminedanisotropic conductive film is used, which takes a lot of time andeffort.

Thus, it is difficult to measure the flexible chip efficiently with highreliability.

Further, a TEG is at risk of electrostatic breakdown through anelectrode pad. Such a problem is caused by exposing an electrode.Therefore, a TEG including as few electrode pads as possible or noelectrode pads, and a method for evaluating such a TEG are effective forimproving the reliability of evaluation of a TEG.

Thus, the invention provides a TEG capable of evaluating characteristicsof a semiconductor element without being in contact with an electrode asmuch as possible or at all by using a wireless technology, an elementsubstrate over which the TEG is formed, and a measuring method thereof.

In order to solve the problems, the following means are used in theinvention.

The invention provides an element substrate provided with a testelementary group (TEG) including a closed loop circuit in which anantenna coil and a semiconductor element are connected in series,wherein a surface of an area over which the closed loop circuit isprovided is covered with an insulating film. The characteristics of asemiconductor element can be evaluated by using the element substrate.

Another mode of the invention provides a flexible element substrateprovided with a TEG including a closed loop circuit in which an antennacoil and a semiconductor element are connected in series. Thecharacteristics of a semiconductor element can be evaluated by using theflexible element substrate.

Another mode of the invention provides an element substrate providedwith a TEG including a closed loop circuit in which an antenna coil, acapacitor, and a semiconductor element are connected in series, whereina surface of an area over which the closed loop circuit is provided iscovered with an insulating film. The characteristics of a semiconductorelement can be evaluated by using the element substrate.

Another mode of the invention provides a flexible element substrateprovided with a TEG including a closed loop circuit in which an antennacoil, a capacitor, and a semiconductor element are connected in series.The characteristics of a semiconductor element can be evaluated by usingthe flexible element substrate.

Another mode of the invention provides an element substrate providedwith a TEG including an antenna coil, a power source circuit, a ringoscillator, and a transistor, wherein the power source circuit suppliesa power source voltage to the ring oscillator, the antenna coil isconnected to a circuit in which load modulation is carried out at theoscillation frequency of the ring oscillator, and a surface of an areaover which the power source circuit, the ring oscillator, and thetransistor are provided is covered with an insulating film. Thecharacteristics of a semiconductor element can be evaluated by using theelement substrate.

Another mode of the invention provides a flexible element substrateprovided with a TEG including an antenna coil, a power source circuit, aring oscillator, and a transistor, wherein the power source circuitsupplies a power source voltage to the ring oscillator, and the antennacoil is connected to a circuit in which load modulation is carried outat the oscillation frequency of the ring oscillator. The characteristicsof a semiconductor element can be evaluated by using the flexibleelement substrate.

Another mode of the invention provides an element substrate providedwith a TEG including an antenna coil, a ring oscillator, a transistor,and an electrode pad for supplying a power source voltage to the ringoscillator, wherein the antenna coil is connected to a circuit in whichload modulation is carried out at the oscillation frequency of the ringoscillator, and a surface of an area in which the power source circuit,the ring oscillator and the transistor are provided is formed of theelectrode pad or an insulating film. The characteristics of asemiconductor element can be evaluated by using the element substrate.

Another mode of the invention provides a flexible element substrateprovided with a TEG including an antenna coil, a ring oscillator, atransistor, and an electrode pad for supplying a power source voltage tothe ring oscillator, wherein the antenna coil is connected to a circuitin which load modulation is carried out at the oscillation frequency ofthe ring oscillator. Characteristics of a semiconductor element can beevaluated by using the flexible element substrate.

According to an inspecting method of the invention, the characteristicsof a semiconductor element are evaluated by applying electromagneticwaves to any of the aforementioned element substrates and measuringpower absorbed by the element substrate.

According to the invention, electromagnetic waves are applied by using ameasuring device capable of discharging a controllable electromagneticwave from an antenna.

According to an inspecting method of the invention, power absorbed by anelement substrate is measured by a magnetic field prober.

By using an inspecting method of the invention, static characteristicsor dynamic characteristics of a semiconductor element provided over anelement substrate can be evaluated in a contactless manner.

According to a manufacturing method of a semiconductor device of theinvention, a TEG including a first semiconductor layer and a thin filmtransistor including a second semiconductor layer are formed over aninflexible substrate; the TEG is inspected in a contact manner; theinflexible substrate is peeled off; the TEG and the thin film transistorare transferred over a flexible substrate; characteristics of the thinfilm transistor is evaluated by inspecting the TEG, which is transferredover the flexible substrate in a contactless manner; and a substratewhich has acceptable characteristics of a thin film transistor is cut.

In another manufacturing method of a semiconductor device of theinvention, a TEG including a first semiconductor layer and a thin filmtransistor including a second semiconductor layer over an inflexiblesubstrate; the TEG is inspected in a contact manner; the inflexiblesubstrate is peeled off; the TEG and the thin film transistor aretransferred over a flexible substrate; the characteristics of the thinfilm transistor are evaluated by inspecting the TEG, which istransferred over the flexible substrate, in a contactless manner; asubstrate which has acceptable characteristics of a thin film transistoris cut; and the thin film transistor over the cut substrate isinspected.

According to a manufacturing method of a semiconductor device of theinvention, voltage-current characteristics of a TEG are evaluated byinspecting in a contact manner; the characteristics of a thin filmtransistor are evaluated by inspecting the TEG, which is transferredover a flexible substrate, in a contactless manner; and a substratewhich has acceptable voltage-current characteristics of a thin filmtransistor is cut.

By the invention, even in the case where it is difficult that ameasurement is carried out by bringing a pin into contact with anelectrode pad, the characteristics of an element can be evaluatedefficiently and with high reliability. Further, electrostatic breakdownof an evaluating element can be suppressed by downsizing the area of anexposed surface of an electrode as much as possible, thereby thecharacteristics of an element can be evaluated with high reliability.Accordingly, a manufacturing process or a parameter used for designingcan be inspected efficiently.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of an element substrate and a measuring deviceof the invention.

FIG. 2 is a circuit diagram showing the principle of evaluating asemiconductor element of the invention.

FIG. 3 is a graph showing a method of evaluating the characteristics ofa semiconductor element of the invention.

FIG. 4 is a circuit diagram formed over an element substrate of theinvention.

FIGS. 5A to 5C are graphs each showing a method of evaluating asemiconductor element of the invention.

FIG. 6 is a circuit diagram formed over an element substrate of theinvention.

FIGS. 7A and 7B are graphs each showing a method of evaluating asemiconductor element of the invention.

FIGS. 8A and 8B are circuit diagrams formed over an element substrate ofthe invention.

FIG. 9 is a circuit diagram of a power source circuit formed over anelement substrate of the invention.

FIG. 10 is a circuit diagram of a power source circuit formed over anelement substrate of the invention.

FIG. 11 is a characteristic curve of a power source circuit formed overan element substrate of the invention.

FIG. 12 is a circuit diagram formed over an element substrate of theinvention.

FIG. 13 is a circuit diagram formed over an element substrate of theinvention.

FIG. 14 is a model diagram of measurement by a spectrum analyzer.

FIG. 15 shows a measurement result of the oscillation frequency of aring oscillator by an oscilloscope.

FIG. 16 shows a measurement result of the oscillation frequency of aring oscillator by a spectrum analyzer.

FIGS. 17A to 17D are views each showing a manufacturing method of asemiconductor device using an evaluating method of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Although the invention will be fully described by way of embodimentmodes and embodiments with reference to the accompanying drawings, it isto be understood that various changes and modifications will be apparentto those skilled in the art. Therefore, unless such changes andmodifications depart from the scope of the invention, they should beconstrued as being included therein. Further, identical portions inconfigurations of the invention may be denoted by the same referencenumerals in different drawings.

Embodiment Mode 1

Description is made on an element substrate including a TEG of theinvention and a measuring method of the characteristics of asemiconductor element using the element substrate with reference to FIG.1.

An element substrate 107 of the invention has as a TEG a configurationwhere an antenna coil 105 and a semiconductor element 106 are connectedin series, that is, a closed loop circuit.

A thin film transistor evaluated by a TEG is provided over the elementsubstrate. A semiconductor device such as a wireless chip is formed bythe thin film transistor. The thin film transistor and the TEG have asimilar configuration, and for example, each has a semiconductor layerformed over a base film. The semiconductor layers of the TEG and thethin film transistor are formed at the same time in the same process. Inaddition, each of the thin film transistor and the TEG has a gateinsulating film provided so as to cover the semiconductor layer, a gateelectrode provided over the semiconductor layer with the gate insulatingfilm interposed therebetween, an insulating film provided so as to coverthe gate electrode and the semiconductor layer, a wire formed at anaperture portion of the insulating film and connected to an impurityarea in the semiconductor layer, and a protective film provided over thewire, and the like. The protective film is preferably formed of aninsulating film containing nitrogen, and provided over the entireelement substrate 107 to prevent an impurity element such as an alkalinemetal from entering the semiconductor layer. The protective film coversthe wire and the like; therefore it becomes difficult to inspect in acontact manner.

In the case of forming a wireless chip, that is, a contactless chip asan example of a semiconductor device, an antenna coil is mounted on thechip, specifically, the antenna coil is connected to a wire which isconnected to an impurity area. Therefore, the antenna coil and the wirecan be formed at the same time. Needless to say, the antenna coil can beformed at the same time as the gate electrode. In this case, however,the antenna coil is required to be connected through a contact hole by aconductive layer so as to be connected to the wire.

Further, there is a case where a contact chip is formed as an example ofa semiconductor device. In this case, the wire for connecting to theantenna coil may be exposed.

Since a TEG has a configuration where the antenna coil 105 and thesemiconductor element 106 are connected in series, the antenna coil ismounted on the TEG. The antenna coil can be formed at the same time as awire or a gate electrode. The antenna coil can be formed from aconductive material such as copper (Cu), silver (Ag), or gold (Au), or alight-transmissive conductive material such as indium tin oxide (ITO) orindium tin oxide containing silicon oxide (ISO). In addition, theantenna coil can be formed by printing, a droplet discharge methodtypified by ink jet, sputtering, a vapor deposition method, or the like.Such an antenna coil is mounted on the TEG, thereby the TEG can beinspected in a contactless manner.

A measuring device 104 includes a radio wave interface 102, an antennacoil 103, a control circuit 101, and the like, and can radiateelectromagnetic waves at predetermined frequency and power.

When electromagnetic waves are radiated from the measuring device 104,induced electromotive force is generated at both terminals of theantenna coil included at least in the TEG over the element substrate 107by electromagnetic induction. Then, a current flows into thesemiconductor element 106 included in the TEG in accordance with elementcharacteristics, which means that a thin film transistor and a wire thatform the semiconductor element 106 provided over the element substrate107 absorb power depending on the characteristics of the semiconductorelement 106. Then, data on the characteristics of the semiconductorelement 106 can be obtained by measuring the amount of power absorbed bythe measuring device 104. Since there is a correlation between thecharacteristics of the semiconductor element 106 and the characteristicsof the thin film transistor, the characteristics of a circuit formed ofthe thin film transistor which forms a semiconductor device can beevaluated and inspected.

A model circuit of the measurement system shown in FIG. 1 is describedwith reference to FIG. 2.

As shown in FIG. 2, the measuring device 104 includes a resonant circuitin which a capacitor having a capacitance C₁, and a coil having aninductance L₁ and a parasitic resistance R₁ are connected in series.Further, a current i₁ and a voltage V are applied to the resonantcircuit. On the other hand, the semiconductor element 106 included inthe TEG over the element substrate 107 has an impedance Z₂, and includesan antenna coil that seems to have an inductance L₂ and a parasiticresistance R₂. Note that the TEG of the invention is not provided with aresonant circuit. Further, the antenna coil of the measuring device 104and the antenna coil 105 of the TEG have a mutual inductance M. Aninduced electromotive force u₂ is generated in such an antenna coil byelectromagnetic waves radiated from the measuring device 104, and acurrent i₂ flows through the antenna coil.

The voltage V applied to the resonant circuit of the measuring device104 in a circuit modeled in FIG. 2 is represented by Formula 1 under theresonant condition (C₁·L₁·ω²=1).

$\begin{matrix}{V = {{R_{1} \times i_{1}} - {M \times \frac{i_{2}}{t}}}} & \left\lbrack {{Formula}\mspace{20mu} 1} \right\rbrack\end{matrix}$

Further, since a current i₂ flowing into the semiconductor element 106is represented by Formula 2 and the induced electromotive force u₂ isrepresented by Formula 3, Formula 4 for the voltage V can be obtained byassigning these formulas. Note that j denotes an imaginary unit.

$\begin{matrix}{i_{2} = \frac{u_{2}}{R_{2} + {j \times \omega \times L_{2}} + Z_{2}}} & \left\lbrack {{Formula}\mspace{20mu} 2} \right\rbrack \\{u_{2} = {M \times \frac{i_{1}}{t}}} & \left\lbrack {{Formula}\mspace{20mu} 3} \right\rbrack \\{V = {{R_{1} + \frac{\omega^{2}M^{2}}{R_{2} + {j \times \omega \times L_{2}} + Z_{2}}}}} & \left\lbrack {{Formula}\mspace{20mu} 4} \right\rbrack\end{matrix}$

Formula 4 shows that there is a proportional relationship between thevoltage V and the current i₁ that are generated in the resonant circuitof the measuring device 104, and a proportionality coefficient isdetermined by ω, R₁, M, R₂, L₂, and Z₂. It is found that in the casewhere the impedance Z₂ of the semiconductor element 106 is changed byfixing ω, R₁, M, R₂, and L₂, the voltage V and the current i₁ arerepresented by a graph shown in FIG. 3. The graph can be divided into anarea in which the impedance Z₂ equals to 0, an area in which theimpedance Z₂ has a certain value, and an area in which the impedance Z₂is infinite. Note that, in the area in which the impedance Z₂ has acertain value, the current i₁ becomes larger with respect to the samevoltage V as the impedance Z₂ is increased.

Since the amounts of the voltage V and the current i₁ that are appliedto the antenna coil 103 of the measuring device 104 can be measured,data on the impedance Z₂ of the semiconductor element 106 of the TEG canbe obtained from them. Based on such a principle, the semiconductorelement 106 can be evaluated in a contactless manner. Then, acorrelation between the characteristics of the semiconductor element 106and the thin film transistor can be obtained since they are manufacturedin the same process. Therefore, the characteristics of the thin filmtransistor, and the characteristics of a circuit and a semiconductordevice formed of the thin film transistor can be inspected by thecharacteristics of the semiconductor element 106.

Subsequently, modes of the invention are described more specifically.

FIG. 4 shows a model circuit configuration of an element substrateprovided with a TEG which uses a diode 401 as a semiconductor elementhaving the impedance Z₂ and includes an antenna coil 402. Note that,although FIG. 4 shows a configuration in which a capacitor 403 isconnected in series to the antenna coil 402 and the diode 401, thecapacitor 403 is not required to be provided. The capacitor 403 isprovided to adjust a phase component of a signal. Therefore, in the casewhere the adjustment is not required, the capacitor 403 is not requiredto be provided. Note that in the case of providing the capacitor 403,capacitance is assumed to be included in the impedance in the formulas.

Subsequently, description is made on a method of evaluating a thresholdvoltage Uth of the diode 401 by using the element substrate shown inFIG. 4.

FIG. 5A is a graph of voltage-current characteristics (referred to asI-V characteristics) of the diode 401, and it is difficult that thecharacteristics are obtained directly without being in contact with anelectrode. On the other hand, FIG. 5B is a graph showing a relationbetween the voltage V and the current i₁ that are generated in theresonant circuit of the measuring device 104, which is obtained by beingmeasured in a contactless manner based on the above-mentioned principle.Note that, in FIG. 5B, a point (V₀, I₀) at which a slope changesdrastically corresponds to a threshold voltage of the diode 401.

By thus obtaining the I-V characteristics of the diode 401 and therelation between V₀ and I₀ of the diode 401, the threshold voltage Uthof the diode 401 can be evaluated by only being measured in acontactless manner. In this way, by obtaining the I-V characteristics ofthe diode 401 and the relation between V₀ and I₀ of the diode 401, thethreshold voltage of the diode 401 can be obtained by the invention.

Practically, a standard element substrate over which an antenna coil anda circuit are formed, which has the same configuration as the TEG, ispreferably measured in a contact manner. Then, the element substrate canalso be measured in a contactless manner. This is because the thresholdvoltage Uth of the diode incorporated in the TEG and the relationbetween V₀ and I₀ that are measured in a contactless manner can beobtained by evaluating the standard element substrate in a contactmanner and measuring the standard element substrate under the samecondition, that is, the condition that the mutual inductance M, theinductance L₂ of the antenna coil, and parasitic resistance R₂ of theantenna coil are kept constant.

Note that the threshold voltage Uth can also be calculated from Formula3 by using the mutual inductance M, the inductance L₂ of the antennacoil, and the parasitic resistance R₂ of the antenna coil. The mutualinductance M, the inductance L₂ of the antenna coil, and the parasiticresistance R₂ of the antenna coil can be obtained by using the elementsubstrate and the measuring device of the invention. L₂ and R₂ of theantenna coil are determined in accordance with the shape and thematerial, and variations in manufacturing can be suppressed. Further,the mutual inductance can be maintained constant by being measured atthe same position under the same measurement environment.

Further, when such a measurement as described in the invention iscarried out for the diode having various threshold voltages Uth, arelation between the threshold voltage Uth of the diode and the voltageV₀ of the measuring device 104 can be obtained, for example, as shown inFIG. 5C.

Once the relation between the threshold voltage Uth of the diode overthe standard element substrate and the voltage V₀ of the measuringdevice 104 is obtained, the threshold voltage of the diode can beevaluated by only being measured in a contactless manner.

As described above, in the case of evaluating element characteristics (avalue such as the threshold voltage) in the invention, it is preferablethat the standard element substrate which can be evaluated in a contactmanner is prepared separately. On the other hand, in the case ofrelatively comparing the element characteristics to be evaluated, forexample, when threshold voltages of a plurality of elements arecompared, or a change over time of a single element is evaluated, thestandard element substrate is not required to be prepared.

Note that, although description is made on the case where a diode isused as the semiconductor element 106 in this embodiment mode, thesemiconductor element 106 may also be an element such as a transistor, aresistor element, or a light-emitting element. Further, thesemiconductor element 106 is not limited to a single element selectedfrom these semiconductor elements. In general, it may be an elementincluding two terminals or a circuit including the element. In the casewhere the diode, the transistor, or the light-emitting element is used,the threshold voltage can be evaluated, and in the case where theresistor element is used, the resistance value can be evaluated. Thus,according to the invention, a parameter (referred to as an elementparameter) which represents element characteristics such as thethreshold voltage or the resistance value can be obtained in acontactless manner. Accordingly, the element characteristics can beevaluated.

The measurement in a contactless manner is not limited to a method ofmeasuring a voltage V and a current i of the measuring device. Ingeneral, the measurement is only required to measure the amount of powerto be supplied from the measuring device 104 and the amount of powerabsorbed by a circuit and the like provided over the element substrate107. For example, the aforementioned evaluation can also be carried outby the voltage V of the measuring device 104 and magnetic fieldintensity obtained from a magnetic field prober that is set on theperiphery of the antenna coil of the element substrate 107. Suchmagnetic field intensity can be measured by using a spectrum analyzer.

As described above, the characteristics of a semiconductor element canbe evaluated in a contactless manner owing to the element substrate ofthe invention. Accordingly, even in the case where it is difficult tocarry out a measurement by bringing a pin into contact with an electrodepad, element characteristics can be evaluated efficiently and with highreliability. Further, electrostatic breakdown of the evaluation elementcan be suppressed, thereby the element characteristics can be evaluatedwith high reliability.

Embodiment Mode 2

Description is made on an evaluation mode of the element substrate ofthe invention, which is different from Embodiment Mode 1.

FIG. 6 shows a model circuit diagram of an element substrate forevaluating a semiconductor element 601 having the impedance Z₂. A TEGprovided over the element substrate includes a circuit in which anantenna coil 602, the semiconductor element 601, and a capacitor 603 areconnected in series, that is, a closed-loop circuit. Note that thecapacitor 603 is not necessarily provided similarly to FIG. 4.

When evaluating the TEG, it is important to determine whethercharacteristics of a semiconductor element are in an acceptable range ina manufacturing process of a semiconductor. Here, description is made ona method of determining whether the characteristics of the semiconductorelement 601 are in an acceptable range by using the element substrateshown in FIG. 6.

First, a TEG of a standard element substrate includes an antenna coiland the semiconductor element 601, which have the same structure as theelement substrate shown in FIG. 6. Then, an element substrate isprepared, over which a plurality of TEGs capable of being measured by inboth a contact manner and a contactless manner are formed. In the caseof carrying out a measurement in a contact manner, a connecting wire ofthe TEG, which is connected to an antenna and the like, is exposed.Further, in the case of carrying out a measurement in a contactlessmanner, an antenna is mounted on the TEG. The TEGs having these modesmay be provided over the same element substrate. Needless to say, eachof the TEGs may be provided over different element substrates.Furthermore, in the case of carrying out a measurement in a contactlessmanner, a flexible substrate can be used as an element substrate.

By using such an element substrate, the semiconductor element 601 ismeasured in a contact manner under the condition that the mutualinductance M, and the inductance L₂ and the parasitic resistance R₂included in an antenna coil are kept constant. Accordingly, a relationbetween V-I characteristics of the semiconductor element 601 and a V-i₁curve of the semiconductor element that corresponds to a result from themeasurement in a contactless manner can be obtained. By measuringfurther more TEGs, and obtaining a V-i₁ area of the semiconductorelement in variations of an acceptable range, the acceptable range canbe obtained.

For example, when acceptable characteristics of the semiconductorelement 601 are shown as a shaded area in FIG. 7A, they can be shown asa shaded area in FIG. 7B on a contactless (V, i₁) plane. The V-Icharacteristics obtained in a contact manner, which are shown in FIG.7A, correlate with the V-I characteristics obtained in a contactlessmanner, which are shown in FIG. 7B, therefore, the acceptablecharacteristics of the semiconductor element 601 can be obtained. Basedon the obtained acceptable characteristics diagram shown in FIG. 7B, thesemiconductor element 601 can be evaluated in a contactless manner.

Once the acceptable characteristics of the semiconductor element 601 areobtained as an area on the (V, i₁) plane, whether the characteristics ofthe semiconductor element 601 is in an acceptable range can bedetermined by only being measured in a contactless manner. Note that therange of the acceptable characteristics can be determined based onspecifications of a semiconductor device.

Note that this embodiment mode can be carried out in free combinationwith the embodiment mode described above.

Embodiment Mode 3

In this embodiment mode, description is made on a manufacturing processof a semiconductor device using the evaluating method described inEmbodiment Mode 2.

As shown in FIG. 17A, a thin film transistor including a semiconductorlayer, which forms a TEG, a chip, and the like is formed over a glasssubstrate 701 which is an element substrate. The thin film transistor isformed over an inflexible substrate such as a glass substrate, therebythe TEG can be inspected in a contact manner. By inspecting the TEG in acontact manner, the V-I characteristics shown in FIG. 7A are obtained(S100 in FIG. 17D). Then, the acceptable characteristic diagram in ameasurement in a contactless manner (V-i₁ curve), which is shown in FIG.7B, is formed (S101 in FIG. 17D).

Subsequently, as shown in FIG. 17B, the glass substrate 701 is peeledoff and a flexible substrate 702 is provided as an element substrate. ATEG over the flexible substrate 702 is inspected in a contactless manner(S102 in FIG. 17D). Then, whether the element substrate has acceptablecharacteristics in the acceptable characteristics diagram shown above isdetermined (S103 in FIG. 17D). The acceptable characteristics mean oneof the parameters of the element substrate.

By inspecting the TEG in a contactless manner, static characteristics ordynamic characteristics of the TEG can also be obtained.

After that, as shown in FIG. 17C, an element substrate determined tohave the acceptable characteristics is cut to each chip (S104 in FIG.17D) and completed (S105 in FIG. 17D). In the abovementioned manner, thesemiconductor device such as a chip can be manufactured.

At this time, each chip may be inspected (S106 in FIG. 17D). In the caseof a chip incorporating an antenna, each chip can be inspected in acontactless manner. In the case of a chip incorporating no antenna, eachchip can be inspected in contact with an antenna connecting terminal.

The process described above is shown by a flowchart in FIG. 17D. Asshown in the flowchart, an element substrate determined to have theacceptable characteristics is cut to each chip and completed. In theabovementioned manner, the semiconductor device such as a chip can bemanufactured.

By such an evaluating method using an element substrate of theinvention, a defect of the semiconductor device such as a chip can beinspected for each element substrate. Accordingly, a high-speed defectinspection of the semiconductor device can be achieved.

Embodiment Mode 4

Description is made on a configuration of an element substrate and anevaluation mode of the invention, which are different from EmbodimentModes 1 and 2.

An element substrate of the invention includes a TEG provided with anantenna coil 804, a capacitor 805, a power source circuit 801, atransistor 803, and a ring oscillator 802 as shown in FIG. 8A. Theantenna coil 804, the capacitor 805, and the power source circuit 801are connected in series. The transistor 803 is connected in parallel tothe capacitor 805 and the antenna coil 804. A gate electrode of thetransistor 803 is connected to an output (Sout) of the ring oscillator802. One terminal of the power source circuit 801 is grounded (GND), andthe other terminal is connected to a power source (VDD) of the ringoscillator 802. The transistor 803 functions as a transistor formodulating the load of the antenna coil 804.

When induced electromotive force is generated in the antenna coil 804over such an element substrate, the power source circuit 801 generates apower source voltage to be supplied to the ring oscillator 802. Beingsupplied with power, the ring oscillator 802 outputs a transmissionsignal and switching of the transistor 803 can be carried out using thetransmission signal. The measuring device 104 can evaluate theoscillation frequency of the ring oscillator 802 by measuring a cyclethat power supply is changed.

As a specific evaluating method, for example, the oscillation frequencyof the ring oscillator is measured to evaluate its relative change. Byevaluating a change over time under various stressful conditions and achange in frequency under various conditions, reliability of the ringoscillator and the power source circuit can be evaluated.

Alternatively, by employing a power source circuit used for an actualwireless chip, the oscillation frequency of the ring oscillator ismeasured. Since there is a correlation between the frequencycharacteristics of a logic circuit in a wireless chip and the frequencycharacteristics of the ring oscillator, the characteristics of thewireless chip manufactured in the same process can be evaluated bymeasuring the oscillation frequency. That is, the capability of a powersource circuit included in the wireless chip can be evaluated by a ringoscillator formed as a TEG.

Further, reliability of the ring oscillator and the power source circuitcan be evaluated by measuring electromagnetic waves radiated from thering oscillator 802 using a magnetic field prober and either a spectrumanalyzer or a oscilloscope.

Further, as described in Embodiment Mode 1 or 2, even in the case ofusing the ring oscillator, a standard element substrate may be prepared.The standard element substrate is provided with a ring oscillator whichcan be measured in a contact manner and a ring oscillator which can bemeasured in a contactless manner. Therefore, dynamic characteristics orstatic characteristics of the ring oscillator, that is, a relationbetween the oscillation frequency and a power source can be evaluated.Further, as described in Embodiment Mode 1 or 2, an acceptablecharacteristic range can be determined by providing more ringoscillators.

Note that as shown in FIG. 8B, the transistor 803 may be omitted as faras the measurement and the evaluation can be carried out. The transistor803 is not required to be provided if load modulation is not required,because the transistor 803 is provided for modulating the load of anantenna coil.

Note that this embodiment mode can be carried out in free combinationwith the embodiment modes described above.

EMBODIMENT Embodiment 1

A specific example of the power source circuit 801 used in EmbodimentMode 4 is described.

In a power source circuit shown in FIG. 9, diodes 901 and 902 areconnected in series, and a capacitor 903 is provided between an outputof the diode 901 and an input of the diode 902. The input of the diode902 is grounded (GND). Such a power source circuit inputs an alternatingcurrent signal with an amplitude Vin to an input of the diode 901, andoutputs a power source voltage Vout. The inputted alternating currentsignal is rectified by the diode 901 and stabilized by the capacitor903.

In a power source circuit shown in FIG. 10, a regulator 1002 is providedat a subsequent stage of a power source 1001 which corresponds to thepower source circuit shown in FIG. 9. The regulator 1002 is a circuitfor holding an output voltage almost constant regardless of an inputvoltage, and a known circuit can be used for the regulator 1002. Thepower source circuit shown in FIG. 10 is preferable in that a stablevoltage can be outputted without depending so much on the amplitude Vinof an alternating current signal to be inputted as shown in FIG. 11.

Embodiment 2

A TEG of the invention can be applied even in the case of being measuredin a contact manner. The less electrode pads are brought into contactwith, the less static breakdown occurs. Further, although it isdifficult that a flexible chip is measured in a contact manner with alarge number of electrode pads, the flexible chip can be measured in acontact manner with a small number of electrode pads in some cases.

In such a case, an element substrate provided with such a TEG as shownin model circuit diagrams of FIGS. 12 and 13 may be used. A TEG shown inFIG. 12 includes a capacitor 1204, an antenna coil 1203, a transistor1202, a ring oscillator 1201, and two power source pads 1205 and 1206. Apower source voltage is supplied from the power source pads 1205 and1206. In addition, a power source (VDD) and a GND of the ring oscillator1201 are connected to the power source pads 1205 and 1206 respectively.Such a TEG is referred to as a ring oscillator evaluation circuit. Thering oscillator evaluation circuit can be described as a circuit capableof measuring oscillation frequency wirelessly.

Such an element substrate having the ring oscillator evaluation circuitcan measure both a power source voltage to be inputted and oscillationfrequency. Therefore, the characteristics of the ring oscillator 1201can be evaluated accurately. Accordingly, the characteristics of acircuit formed of a thin film transistor can be evaluated accurately.

As a configuration to decrease the number of electrode pads, a pluralityof ring oscillator evaluation circuits 1301(1) to 1301(n) may beconnected in parallel using two electrode pads 1302 and 1303 in common.By connecting the plurality of ring oscillator evaluation circuits,characteristics evaluation can be carried out more accurately.

Note that this embodiment can be freely combined with the embodimentmodes described above, or substituted by the TEG of the embodiment modesdescribed above.

Embodiment 3

In this embodiment, description is made on a measurement result of anelement substrate having a ring oscillator evaluation circuit by aspectrum analyzer.

As shown in FIG. 14, an antenna coil for a spectrum analyzer 144 isinserted between a pair of bases 140 supported by a spacer 141. A picoprobe pin 142 is brought into contact with an evaluation elementsubstrate 143 having a ring oscillator evaluation circuit which isdisposed over one of the bases, thereby, measurement frequency isoutputted to a connected oscilloscope. Note that 51 stages of ringoscillators are disposed, a channel width of an n-channel thin filmtransistor is set to 10 μm, the channel width of a p-channel thin filmtransistor is set to 20 μm, the channel length of both of the thin filmtransistors is set to 1 μm, and the thickness of a gate insulating filmis set to 40 nm. Further, the n-channel thin film transistor has an LDDstructure and the p-channel thin film transistor has a single drainstructure.

FIG. 15 shows a measurement result of the oscillation frequency of aring oscillator by an oscilloscope. FIG. 16 shows a measurement resultof the oscillation frequency of a ring oscillator by a spectrumanalyzer. Since a wave form shown in FIG. 15 almost corresponds to awave form shown in FIG. 16, it is found that the oscillation frequencyof a ring oscillator evaluation circuit can be measured in a contactlessmanner by a spectrum analyzer using a contactless antenna.

This application is based on Japanese Patent Application serial no.2005-061717 filed in Japan Patent Office on 7 Mar., 2005, and the entirecontents of which are hereby incorporated by reference.

1. An element substrate comprising: a test elementary group including aclosed-loop circuit in which an antenna coil and a semiconductor elementare electrically connected in series, wherein a surface of an area overwhich the closed-loop circuit is provided is covered with an insulatingfilm.
 2. An element substrate comprising: a test elementary groupincluding a closed-loop circuit in which an antenna coil and asemiconductor element are electrically connected in series, wherein theelement substrate has flexibility.
 3. The element substrate according toclaim 1 or 2, wherein the semiconductor element is any one of a diode, atransistor, a light-emitting element, a resistor element, and acapacitor.
 4. The element substrate according to claim 1 or 2, furthercomprising: a capacitor provided in the closed-loop circuit, wherein thecapacitor, the antenna coil and the semiconductor element areelectrically connected in series.
 5. An element substrate comprising: anantenna coil, a ring oscillator, a power source circuit for supplying apower source voltage to the ring oscillator, and a circuit in which loadmodulation is carried out at an oscillation frequency of the ringoscillator, wherein the antenna coil is electrically connected to thecircuit.
 6. An element substrate comprising: an antenna coil, a ringoscillator, a power source circuit for supplying a power source voltageto the ring oscillator, and a circuit in which load modulation iscarried out at an oscillation frequency of the ring oscillator, whereinthe antenna coil is electrically connected to the circuit, and whereinthe element substrate has flexibility.
 7. An element substratecomprising: an antenna coil, a ring oscillator, a circuit in which loadmodulation is carried out at an oscillation frequency of the ringoscillator, and an electrode pad for supplying a power source voltage tothe ring oscillator, wherein the antenna coil is electrically connectedto the circuit.
 8. An element substrate comprising: an antenna coil, aring oscillator, a circuit in which load modulation is carried out at anoscillation frequency of the ring oscillator, and an electrode pad forsupplying a power source voltage to the ring oscillator, wherein theantenna coil is electrically connected to the circuit, and wherein theelement substrate has flexibility.
 9. The element substrate according toany one of claims 5 to 8, wherein the circuit comprises a transistor forperforming load modulation.
 10. An inspecting method of an elementsubstrate comprising: applying an electromagnetic wave to the elementsubstrate comprising a test elementary group including a closed-loopcircuit in which an antenna coil and a semiconductor element areelectrically connected in series; and evaluating characteristics of thesemiconductor element by measuring power absorbed by the elementsubstrate.
 11. An inspecting method of an element substrate comprising:applying an electromagnetic wave to the element substrate comprising atest elementary group including a closed-loop circuit in which anantenna coil and a semiconductor element are electrically connected inseries; and evaluating characteristics of the semiconductor element bymeasuring power absorbed by the element substrate, wherein the elementsubstrate has flexibility.
 12. The inspecting method of an elementsubstrate according to any one of claims 10 to 11, wherein the powerabsorbed by the element substrate is measured by a magnetic fieldprober.
 13. The inspecting method of an element substrate according toany one of claims 10 to 11, wherein static characteristics of thesemiconductor element is evaluated in a contactless manner.
 14. Aninspecting method of an element substrate comprising: applying anelectromagnetic wave to the element substrate comprising an antennacoil, a ring oscillator, a power source circuit for supplying a powersource voltage to the ring oscillator, and a circuit in which loadmodulation is carried out at an oscillation frequency of the ringoscillator; and evaluating characteristics of the ring oscillator bymeasuring power absorbed by the element substrate.
 15. An inspectingmethod of an element substrate comprising: applying an electromagneticwave to the element substrate comprising an antenna coil, a ringoscillator, a power source circuit for supplying a power source voltageto the ring oscillator, and a circuit in which load modulation iscarried out at an oscillation frequency of the ring oscillator; andevaluating characteristics of the ring oscillator by measuring powerabsorbed by the element substrate, wherein the element substrate hasflexibility.
 16. The inspecting method of an element substrate accordingto any one of claims 14 to 15, wherein the power absorbed by the elementsubstrate is measured by a magnetic field prober.
 17. The inspectingmethod of an element substrate according to any one of claims 14 to 15,further comprising: measuring an electromagnetic wave radiated from thering oscillator.
 18. The inspecting method of an element substrateaccording to any one of claims 14 to 15, wherein static characteristicsof the ring oscillator is evaluated in a contactless manner.
 19. Amanufacturing method of a semiconductor device comprising: forming atest elementary group including a first semiconductor layer, and a thinfilm transistor including a second semiconductor layer over a firstsubstrate; inspecting the test elementary group in a contact manner;peeling the test elementary group and the thin film transistor from thefirst substrate; transferring the test elementary group and the thinfilm transistor over a second substrate; evaluating characteristics ofthe thin film transistor by inspecting the test elementary grouptransferred over the second substrate in a contactless manner; andcutting off the second substrate.
 20. A manufacturing method of asemiconductor device comprising: forming a test elementary groupincluding a first semiconductor layer, and a thin film transistorincluding a second semiconductor layer over a first substrate;inspecting the test elementary group in a contact manner; peeling thetest elementary group and the thin film transistor from the firstsubstrate; transferring the test elementary group and the thin filmtransistor over a second substrate; evaluating characteristics of thethin film transistor by inspecting the test elementary group transferredover the second substrate in a contactless manner; cutting off thesecond substrate; and inspecting the thin film transistor over the cutsecond substrate.
 21. The manufacturing method of a semiconductor deviceaccording to any one of claims 19 to 20, further comprising: obtainingvoltage-current characteristics of the test elementary group by thecontact inspection;
 22. The manufacturing method of a semiconductordevice according to any one of claims 19 to 20, wherein the firstsemiconductor layer and the second semiconductor layer are formed overthe first substrate in the same process.
 23. The manufacturing method ofa semiconductor device according to any one of claims 19 to 20, whereincharacteristics of the thin film transistor over the cut secondsubstrate are in an acceptable range.